In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date:                (i) part of common general knowledge; or        (ii) known to be relevant to an attempt to solve any problem with which this specification is concerned.        
The term ‘foodstuff’ as used in this specification is intended to include any natural or processed food item that respires or breathes. Fresh produce (fruits and vegetables) is one example of a food item that is known to respire and is accordingly encompassed by the description ‘foodstuff’ as used herein. Accordingly some of the description of the invention which follows is directed to respiring produce, although it will be appreciated that the description is not intended to be so limited and encompasses other foodstuffs such as breads, and seafood, for example, live crustaceans.
The preservation of foodstuffs is an important issue for a number of reasons. Firstly, appropriate preservation techniques allow the producer of the foodstuff to be able to give assurances to customers that the product delivered will be in a form which is acceptable to them and to end users of the product. Secondly, appropriate preservation techniques can permit the shelf life or keeping of the product to be extended.
It is known that produce continues to draw oxygen from the atmosphere even following harvesting or picking, and converts it to gaseous carbon dioxide with some water vapour and other gases, which are then transmitted into the atmosphere.
It is also known that changes in the carbon dioxide and oxygen levels around the produce, as well as the level of other gases, can affect the storage life of the produce.
Temperature is another factor known to affect the rate of respiration of produce. For example, a temperature increase of 5 degrees Celsius is thought to contribute to a doubling of the respiration rate of some produce.
It is therefore important to try and slow the rate of respiration to reduce or delay the degree of spoilage of the produce.
A number of methods to control the respiration rate of produce are known in the prior art.
One method comprises so-called modified atmosphere packing, which involves adding a flushing or purging gas to a chamber in which the produce has been placed for storage or transport, so as to reduce the amount of oxygen in the chamber available to be consumed by the produce in the chamber. Often such chambers are fitted with temperature controls to control the temperature of the atmosphere inside the chamber.
Another method comprises the use of controlled permeability films in which the produce is placed for storage or transport. These films are, to a degree, capable of dictating to respiring produce the rate of transmission of oxygen from the atmosphere to the produce. In addition, the amount of carbon dioxide generated by the produce and present in the atmosphere immediately surrounding the produce, can be controlled.
U.S. Pat. No. 5,807,630 discloses one example of a controlled permeability film. The film comprises a film forming polymer, a dispersing polymer, and an inert porous filler. The filler may have a surface modifying agent coated thereon.
Australian Patent No 647410 discloses another example of a film to develop and maintain a controlled atmosphere. The film described comprises a polyethylene film impregnated with porous activated earth particles.